Nowadays, people's life increasingly relies on various network applications. In the face of soaring demand for network transmission, how to save network resources and reduce pressures on network transmission becomes a burning issue.
When a user accesses a web page, the browser will send a request to a corresponding server for obtaining the corresponding web page; upon receiving the request, the server will return a response to the user's browser to indicate a file to be loaded by the user's browser and a corresponding address. The browser will cache obtained files locally in order to reduce pressures on network transmission and prevent the user from obtaining corresponding files each time he/she accesses the web page. If the user needs a file once again when accessing the web page, the browser will check whether the file has been cached; if the file has been cached and does not expire, then the browser will directly use the file without obtaining it through the network. If the file expires, then the browser will request a corresponding server for the file. Using this method, pressures on network transmission can be reduced to some extent. However, where cached files expire, there still exists huge file transmission, and therefore the solution needs further optimization.